Core send back is optional. Refund will be given when i receive core back. Buyer pays for shipping. This is a oem re manufactured transfer case actuator for x3  and x5  vehicle. (DOES NEED A magnet SENSOR, you must take it off your old part and install in this one) SEE PICTURES Please double check part numbers to make sure it will work on your vehicle. These actuators have been taken apart amd fixed. Actuators have been cleaned, worn out parts replaced and re greased. Motors have been load tested. I will guaranty the part for 30 days. I can replace the part with another one or give out a full refund when part is returned. Please feel free to email me if you have any questions about the part or vehicle compatibility. Part will ship out 1-2 days after payment has been received but i will try to get it out same day. Thanks for looking and have a nice day.